In video surveillance, not only monitoring an area is important, but also recording the video images. For example, when events in places frequented by large numbers of people, such as public squares, stadiums and traffic intersections, are automatically monitored using cameras, in addition to viewing the live images, recording the images is also of great importance. Due to the limited storage capacity of the monitoring systems, however, only a small number (approximately 1-5 frames per second) of the total number of captured images (approximately 50 frames per second) are recorded. Thus, the quantity of information available for evaluation is decreased. When event sequences in the location occur relatively rapidly, images of significant interest might not be recorded, causing them to be irretrievably lost. For example, the frames of a sequence captured at a traffic intersection that best allow detail to be recognized might not be stored for future analysis. Newer systems and compression algorithms have been developed that have significantly increased the rate at which the captured images can be recorded. Some newer systems even permit real-time recording in which all of the images captured by the camera are recorded. In addition, the capacity of the image archives has been increased.
Existing methods do not, however, permit the increased amount of video data stored in image archives to be optimally processed and evaluated. One known method of processing video data involves extracting basic elements (called primitives) from a video sequence and storing them along with the video sequence. Then the stored primitives, as opposed to the entire video sequence itself, are analyzed in order to search for an event. In order to locate the event, it is not necessary to analyze the entire video, but rather only the primitives that correspond to the video. This video processing method is described in WO 2006/107997 A2. Methods for decreasing the cost of processing the captured video data or for searching the processed video data, however, are not disclosed.
A method is sought for decreasing the cost of processing video data recorded in real-time and for searching the processed video data.